1. Field of the Invention
The present invention relates generally to a turbopump for a rocket engine, and more specifically to an apparatus and a process for checking the rotor torque of a turbopump.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
A rocket engine of the type used to pressurize a fuel or an oxidizer includes a rotor driven by a turbine with one or more impellers connected to the common rotor shaft such that the turbine drives the one or two pumps. A turbopump for a rocket engine requires a relatively high amount of maintenance between uses. In order to achieve a high payoff turbopump with a low investment, a modern turbopump in space propulsion programs is required to have greater service life with lower maintenance costs. In order to achieve lower maintenance costs, the turnaround time between mission cycles must be kept to a minimum. At each cycle, one item on the maintenance checklist to be conducted is a rotor torque check.
In order for a turbopump to be returned to service, among other requirements, it must be clear of all FOD (Foreign Object Damage) as well as free from any damage to the rotor or bearings. One maintenance check that is a valid indicator of FOD or rotor and bearing damage is a rotor torque check. This is when the rotor is turned and the amount of torque resistance is measured. An undamaged rotor will turn with less torque than would a damaged rotor. Failure of a turbopump due to rotor or bearing damage may lead to an event categorized as a Criticality 1 (loss of life or vehicle) failure mode.
In modern turbopumps for a rocket engine, performing a rotor torque check involves timely and costly maintenance procedures. In many cases, inlet piping or structural cases must be removed in order to expose the turbopump rotor. As each piece of hardware is reinstalled, they routinely must undergo lengthy quality checks to ensure proper assembly and function.